This invention relates to an exhaust gas purifying device for a marine engine and more particularly to an improved, simplified and highly effective system for treating the exhaust gases of an engine prior to their discharge to the atmosphere.
In many types of applications for internal combustion engines, the engine exhaust gases are delivered to the atmosphere through alternate exhaust gas discharges. For examples, in connection with outboard motors, it is normally the practice to discharge the exhaust gases through an underwater exhaust gas discharge when traveling at high speeds. However, when traveling at lower speeds and when the high speed exhaust gas discharge is more deeply submerged, the exhaust gases are normally delivered directly to the atmosphere through an above the water exhaust gas discharge. Although such arrangements are satisfactory, if it is desired to treat the exhaust gases with a catalyzer so as to prevent the discharge of unwanted exhaust gas constituents to the atmosphere, the system for treating the exhaust gases can be extremely cumbersome.
It is, therefore, a principal object of this invention to provide a relatively simple and highly effective arrangement for treating the exhaust gases of an internal combustion engine in which the exhaust system has two different atmospheric discharges.
It is a further object of this invention to provide an improved, simplified and high effective system for treating the exhaust gases of an internal combustion engine before their discharge to the atmosphere through either of two alternative exhaust gas discharges.
In the outboard motors, like many other applications, it is necessary to insure good contact between the exhaust gases and the catalyst in order to insure effective treatment before discharge to the atmosphere. Also, it is necessary to insure that the catalyst operates at the necessary temperature so as to achieve the desired exhaust gas treatment. Normally, it has been the practice to cause the exhaust gases to flow through a catalyst bed in order to achieve the desired treatment. However, this can present certain difficulties in that restrictions to the flow of exhaust gases may be unduly high under some circumstances. Also, it is frequently necessary to use different catalyzers and the passage of the exhaust gases through a series of catalyzers can give rise to objectionable restrictions.
It is, therefore, a still further object of this invention to provide an improved catalyzer system for treating the exhaust gases without introducing large restrictions to exhaust gas flow.
It is yet a further object of this invention to provide an improved catalyzer system for an internal combustion engine wherein treatment of the exhaust gases is achieved without introducing substantial flow restrictions.
The problem of treating the exhaust gases in an outboard motor is particularly acute. One of the main reasons for this is due to the extremely compact nature of an outboard motor. In order to provide effective catalyzer treatment, it is normally the practice to use large catalyst beds and this is simply not practical with an outboard motor.
It is, therefore, a still further object of this invention to provide an effective catalyzer system for an outboard motor in which the exhaust gases can be effectively treated in a compact area.